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Hi everyone, it's been a long time since I've posted on this forum, but now I have a question which might ring a bell with someone.
I have just completed the Moto Piston Rally on my 1978 500 Strada, it's about the 4th time I've done it on this bike and once again it was pretty trouble-free - except for an oil leak. Since I rebuilt the engine a few years ago, it's been completely oil tight, but not now it isn't! It's very difficult to spot exactly where it's coming from, but it seems to be from the area of the rear cylinder head gasket, but there's oil everywhere now. It didn't affect running and the rear plug isn't showing any contamination. The front cylinder is clean and the rocker box breathers are in place.

Before I start tearing it apart, I thought I'd ask if anyone has had a similar problem and invite comments.
Regards,
Joe.

First check rocker cover gasket as oil from here can run down to the head/cylinder joint
Yet it is probably the head gasket given your description
You could clean everything up and after a short run try to see where the oil is coming from

Good luck, have fun Ian

PS Some early 501 Camel cylinders are porous and oil escapes from the push rod tunnels and runs back and down the fins

I did a few if these rallies about 13 years ago ish on a beemer.
I have once had a weep of oil collecting around the rear of the rear cylinder which was coming from the crankcase joint near the “earth lead “bolt.
Guess the main breather is not the culprit.
You will have to try washing it clean then checking after a short ride.
My 501 gets a damp front fin on the fin rather annoyingly above the head joint one.
John

Hi John,
Thanks for your suggestions. I think you're right, I'll have to give it a good clean, take it for a run and see what happens. There is so much oil and muck all over it now after the rally, I could convince myself of almost anything! Still, once again, the bike has been great and it is ideally suited to those tortuous mountain roads.

I'll post something when I get to the bottom of it, but it won't be soon because I'm in the throes of moving house. Such fun....

Joe.

I found moving the house contents simple, moving the contents of garage and greenhouse tricky.Only three times so far.
John

Hi Joe,

Once you have given it a thorough clean, wash the affected area with brake cleaner and dry off.
Liberally coat the joints/area suspected of leaking with talcum powder and once running you will soon be able to see where the oil is coming from by the nice black area on the white talc. Having established the location of the leak, simply wash the talc off with soapy water.
You could be posh and use proper crack detector developer in an aerosol as it gets in between the fins a bit better, but it is a lot more expensive than talc.

Hope the move goes OK. Going far away?

Regards,
George.